Production of hydrated chromic chloride



hated by dissolved lead.

Patented it 26, 1932 dt'lES BRUDE AND CARL 'WUBSTER, OI LUDWIGSHAFEN-ON-THE-BHINE, GEBF my, ASSIGNOBS TU GENERAL ANILINE WORKS, INC,

"CORPORATION 01' DELAWARE or NEW YonxfiN. Y, A

PRODUCTION 0] HYDRATED 'CHROmC CHLORIDE l l'o Drawing llrliinal application filed 3111:! 30, 1926, Serial No. 126,085,11111 in Germany Iarch 11, 1926.

lflrrlderl and this application med December 19, 1928. Serial No. 827,188.

The present invention relates to the production or hydrated chromic chloride from anhydrous salt.

The present application is divided out from our cope-r ding application for the manufacture of chromium chloride Ser. No. 126,085, tiled July 30, i920.

l lle have iound that anhydrous chromic chloride can he easily dissolved in Water by enposing its aqueous suspension to the action ot a cathodically polarized conductor, l or enannple, a cathode of a metal, such as lead is employed with an anode of graphite. in order to avoid contamination of the solution by oxidation products termed at the anode, the anode may he surrounded by a diaphragm; it is, however, more suitable to rnalre the anode of chromium, vvherehy a diaphragm may he dispensed with.

The process is prelerahly carried out in a lead vessel employed as cathode The cur,- rent density required for causing dissolution oil" the anhydrous salt is very small; for example less than 0.02 ampere per square decirneter oi the electrode surface is sufficient. llven large quantities of chromic chloride can thus he dissolved in a few minutes. By reason ol" the cathodic polarization of the lead vessel, the chromic chloride is not contamilts the dissolution of anhydrous chromic chloride is en exothermic reaction, the temperature oi the solution rises to hoiling, so that highly concentrated chromic chloride solutions can he obtained at once and these on cooling solidify entirely or partly to laydrated chromic chloride.

'llhe process is of particular advantage for the purification oi chromic chloride containing corhon as ohtained, for instance, by treatlug term-chromium with chlorine. In this case the hot chromic chloride solutions ohtained in the manner described above are filtered, hetero losing allow d to solidify,

mic chloride to the action of a po arized cathode and filtering the solutions while hot.

3. A process for the production of high grade chromic chloride which comprises exposing an aqueous sigspension of sub drous chromic chloride to the action of a po arized cathode at a current density of about .02 ampere per square decimeter,

In testimony whereof, we afiix our signatures.

J OHANNES BRODE. CARL WURSTER. 

